An Integrated Approach to Assess the Water Efficiency of Introducing Best Management Practices: An Application to Sugarcane Mechanisation in Brazil

Management practices reputed to be the best are being introduced widely in the agricultural sector. The identification of what these best management practices are for a given cultivation area requires thorough assessment, using indicators that reduce the risk of unintended impacts and that help manage environmental and economic trade-offs. We propose an integrated assessment that includes two indicators in water footprint sustainability assessment: water apparent productivity and ecosystem services value, thereby considering the trade-offs in the two ecosystem services of water provisioning and erosion potential. The approach was tested in Mogí-Guaçú Pardo (Brazil), a basin that has been subjected to intensive land-use changes through the expansion of sugarcane plantations. Here, regulatory changes have also promoted the introduction of the new management practice of mechanised harvesting, thereby phasing out the practice of burning the fields before manual harvest. A probabilistic approach was applied to account for uncertainty in model parameters. The results reveal that sugarcane has a comparably high economic value but is a less efficient land-use type from a water-use perspective. The total green and blue water footprint in the basin increased by 12% from 2000 to 2012, mainly due to the increase in sugarcane area (+36%). The intensification in sugarcane harvesting practices led to improved economic water-use efficiency and also lowered erosion costs. Adding the new indicators and considering trade-offs linked to new management practices and/or land-use changes allow for more robust decision making

An accurate evaluation of water availability in sub-arid Mediterranean watersheds through SWAT: Cega-Eresma-Adaja

Simulation of flow processes in hyper-regulated Mediterranean watersheds is critical when examining general water demand and established ecological flows of River Basin Management Plans. Weather dynamics in the Mediterranean zone in recent decades have been characterised by a natural variation of drought cycles. In addition, exacerbated climate change proves that water fluxes must be estimated with more exhaustive models. The aim of this study is to assess the water balance of the Cega-Eresma-Adaja (CEA) watershed, including a detailed assessment of land uses and management practices to quantify agricultural water demand for the time period 2004–2014. We used the Soil and Water Assessment Tool (SWAT), given that it is a widespread tool that involves complex processes of the water cycle on a basin scale, providing information on water dynamics related to land use as a fundamental characteristic for water balance calculation. The Nash-Sutcliffe coefficient efficiency value, the main index of calibration and validation performance, was 0.86 for the Eresma-Adaja River and 0.67 for the Cega River. This presents a good result considering the large-scale watershed studied. Analysing dry hydrological years, we found that the estimation of ecological flows for sub-arid zones needs to consider the shallow aquifer-river relationship. During spring-summer periods, with very low flow, monitoring the shallow aquifer levels ensures a good ecological status. The study reveals that aspects such as crop rotation, soil management and their associated measures in Mediterranean basins are key factors for water resource management during drought periods. These results are expected to serve stakeholders and river basin authorities in conducting better-integrated water management practices in the watershed

Cross-sectoral implications of the implementation of irrigation water use efficiency policies in Spain: A nexus footprint approach

One technical solution often suggested for alleviating water scarcity is to increase the efficiency of irrigation water use. In Spain, several plans have been launched since 2000 to upgrade irrigation infrastructures and thereby achieve water savings equivalent to 2500 hm3/year and promote rural development. The present study uses a footprint approach to evaluate the impacts on land, water, energy, and carbon emissions of the implementation of irrigation modernization policies in agriculture in Spain between 2005 and 2011. The results show that during the period studied, the irrigated area remained stable (+0.3%), although there was a shift in crop patterns, with low-value non-permanent crops being replaced by high-value permanent crops. The water demand for irrigation decreased by 21%; half of this is explained by the shift in crop patterns and the reduction of the consumptive fraction (i.e., blue water footprint), and the other half by the cutback of return flows associated with the higher efficiency of the irrigation infrastructure. Changes in water demand have been accompanied by a progressive substitution of surface water for groundwater. Reduced water demand for irrigation has brought a reduction of 13% in water’s energy footprint and 25% in its carbon footprint. In relative terms, water efficiency (m3 consumed/m3 irrigated) has increased by 8%, although this has also increased the energy intensity (kWh/m3) to 9%. The emission rate (kgCO2 equiv/m3 irrigated) has decreased by 12% as a result of the drop in the emission factor of electricity production. Overall, irrigation modernization policies in Spain have supported the transition from an irrigation sector that is less technified and heavily dependent on surface water into one that is more productive and groundwater-based. From a resource-use perspective, such transition has contributed to stabilizing or even decreasing the irrigated land, and surpass the annual water savings target of 2500 hm3, although it has also made the sector more energy-dependent. Despite the overall positive outcomes, the observed water savings are masked by various synergistic factors, including favorable climatological conditions toward the end of the study period, which contributed strongly to curbing overall irrigation water demand. In the light of the higher frequency of observed droughts in Spain, the investments done so far do not guarantee that the planned water saving targets can be sustained if not complemented with additional measures like restricting irrigated area and/or setting caps for water intensive crops

Sustainable development pathways to water, food, and energy security in the Zambezi basin

The Zambezi basin has enough resources to meet its development targets but doing so sustainably will require making strategic choices that deviate from the prevailing development paradigm and investing in the outstanding natural capital of riparian countries

Enhancing LULC scenarios impact assessment in hydrological dynamics using participatory mapping protocols in semiarid regions

Land use and land cover (LULC) scenarios in rural catchment hydrology are crucial to describe the effects of future water dynamics. However, there is a lack of understanding of the effectiveness of including static land covers at the subbasin level to provide inter-annual stability in changing the different water balance components. We developed a step-by-step mapping protocol to extend and enrich the hydrological assessment of future LULC scenarios defined through participatory stakeholder involvement. This novelty included specific allocation of static and dynamic LULC change among the scenarios and then compared the change of water dynamics to the current situation. For this, we quantified the LULC impact on the components of the water balance from three contrasting participatory scenarios implemented with the SWAT model in a rural basin in central Spain. The Land-sharing scenario (LSH) had the highest percentage of permanent grassland and shrubs and no increase of irrigated land compared to baseline. The land-sparing scenario (LSP) intensified agricultural land use close to urban areas, and the land balance scenario (LBA) was intermediate. The LSH increased the aquifer recharge by +1.7% and streamflow by +1.5%, while evapotranspiration and soil water storage decreased by -0.2%. In contrast, the LBA decreased in the riverine flux of -0.5%, an aquifer recharge of -0.6%, a soil water storage of -3.5%, and an evapotranspiration rate of +0.3%. Thus, LSH revealed that the allocation of permanent land cover such as grassland could buffer water dynamics, suggesting that dedicated planning and allocation of permanently vegetated LULC will favour land and water conservation

Cooperation and joint investments are key to sustainable development in the Indus basin

Achieving sustainable development in the Indus basin will strongly depend on the capacity of riparian countries to realize the opportunities that arise when cooperation and joint investments across sectors and countries are embraced

Biophysical and sociocultural factors underlying spatial trade-offs of ecosystem services in semiarid watersheds

Biophysical and social systems are linked to form social-ecological systems whose sustainability depends on their capacity to absorb uncertainty and cope with disturbances. In this study, we explored the key biophysical and socio-cultural factors underlying ecosystem service supply in two semiarid watersheds of southern Spain. These included variables associated with the role that freshwater flows and biodiversity play in securing the system’s capacity to sustain essential ecosystem services and their relationship with social demand for services, local water governance, and land-use intensification. Our results reveal the importance of considering the invisible dimensions of water and biodiversity, i.e. green freshwater flows and trait-based indicators, because of their relevance to the supply of ecosystem services. Furthermore, they uncover the importance of traditional irrigation canals, a local water governance system, in maintaining the ecosystems’ capacity to supply services. The study also highlights the complex trade-offs that occur because of the spatial mismatch between ecosystem service supply (upstream) and ecosystem service demand (downstream) in watersheds. Finally, we found that land-use intensification generally resulted in losses of the biophysical factors that underpin the supply of some ecosystem services, increases in social demand for less diversified services, and the abandonment of local governance practices. Attempts to manage social-ecological systems toward sustainability at the local scale should identify the key biophysical and socio-cultural factors that are essential for maintaining ecosystem services and should recognize existing interrelationships between them. Land-use management should also take into account ecosystem service trade-offs and the consequences resulting from land-use intensificationFunding for the development of this research was provided by a postdoctoral grant from the Spanish National Institute for Agriculture and Food Research and Technology (INIA), which is cofunded by the Social European Fund; the Seventh Framework Programme of the European Commission (FP7, 2007-2013) under the BESAFE project (Biodiversity and Ecosystem Services: Arguments for our Future Environment, Contract No. 282743; http://www.besafe-project. net); and the OpenNESS Project (Operationalisation of Natural capital and Ecosystem Services: From Concepts to Real-World Applications, Contract No. 308428

Situational Analysis of the Upper Bhima sub-basin in the context of the Water-Food-Biodiversity Nexus

This report was prepared as part of a research project titled “Soft systems analysis: Streamlining participatory approaches and agent-based models to explore ideas of fairness at the food-water-biodiversity (F-W-B) nexus (fairSTREAM)”. This project is funded by the International Institute for Applied System Analysis (IIASA) and is implemented in collaboration with two partners from India: Society for Promoting Participative Ecosystem Management (SOPPECOM) and Indian Institute of Science Education and Research Pune (IISER Pune). The project started in September 2021, and it will run till December 2024. The main goal of fairSTREAM is to develop and demonstrate a co-production methodology for including equity and justice (fairness) alongside efficiency in developing sustainable policy options across the Water-Food-Biodiversity nexus (WFB nexus). The demonstration component is placed in the Upper Bhima basin, and the specific objectives here are to design and test a systems-informed stakeholder knowledge co-production process with the purpose of developing fair and sustainable policy options for the WFB nexus. The co-production process involves several steps, namely: the assessment phase (including preparatory work, problem framing, and exploration of options) and the action planning phase. An evaluation process is also embedded across the different steps and phases. This report summarizes the findings of the preparatory and problem-framing phase, to contextualize the WFB nexus in the Upper Bhima, and what specific challenges it raises, both from a sustainability, equity, and fairness perspective. Other than serving as a reference document for primary stakeholders - farmers, fishers, and forest-dependent communities to contextualize the WFB nexus in the Upper Bhima, this situational analysis is intended to inform future phases, including the development and co-production of options using a combination of modeling and soft approaches